Variation of the Reach-scale Channel Geometry in the Braided Reach of LYR after the Operation of XLD Reservoir
The Lower Yellow River (LYR) has experienced continuous channel degradation since the operation of water impoundment and sediment detention of the Xiaolangdi (XLD) Reservoir,and therefore significant variation of the channel geometry has occurred in the LYR.The channel evolution of the braided reach plays a key role in the channel adjustment of the LYR.In this paper,measured profiles of 28 sedimentation sections were collected in the braided reach of the LYR over the period from 1999 to2010,and the reach-scale characteristic parameters under the bankfull stage were estimated using a composite method which integrates the geometric mean based on the logtransformation with the weighted average based on the distance between two consecutive sections.Recent variation of the reach-scale channel geometry in the braided reach was investigated.In the BaiHeZhen-Huayuankou (BHZ-HYK) reach,the reach-scale bankfull width increased from 1,055 m in 1999 to 1,375 m in 2010,with the corresponding bankfull depth increasing from 1.45 m to 3.60 m,which led to an increase of 3,421 m2 in the corresponding bankfull area; In the Huayuankou-Jiahetan (HYKJHT) reach,the reach-scale bankfull width increased from 1,136 m to 1,846 m,and the bankfull depth increased by 1.17 m,which led to an increase of 3,136 m2 in the corresponding bankfull area; In the Jiahetan-Gaocun (JHT-GC) reach,the reach-scale bankfull width increased from 611 m to 823 m,with the bankfull depth increasing from1.97 m to 3.73 m,and the corresponding bankfull area was increased by 1,864 m2.In the braided reach,the reach-scale bankfull area increased by about 200% as the bankfull width increased by 43% and the bankfull depth was doubled.In the braided reach,the reach-scale regime coefficient decreased by 40% from 19.9 to 11.4,and therefore,the channel adjustment in the braided reach was characterized mainly by channel incision,also accompanied by significant channel widening.
channel geometry braided reach reach-scale channel geometry lower Yellow River channel incision channel widening
Li Xiaojuan Xia Junqiang Zhang Xiaolei
State Key Laboratory of Water Resources and Hydropower Engineering Science,Wuhan University, Wuhan, 430072, China
国际会议
The 5th International Yellow River Forum (第五届黄河国际论坛)
郑州
英文
311-317
2012-09-24（万方平台首次上网日期，不代表论文的发表时间）